A STUDY  OF  THE  PRODUCTS  OBTAIN- 
ED  FROM  AN  EASTERN  BITUMINOUS 
COAL  USING  DIPHENYL  ETHER 
AND  PHENOL  AS  SOLVENTS 


GEORGE  ERNEST  KELLER 


THESIS 


FOR  THE 


DEGRE  E OF  BACHELOR  OF  SCIENCE 

IN 

CHEMICAL  ENGINEERING 


COLLEGE  OF  LIBERAL  ARTS  AND  SCIENCES 


UNIVERSITY  OF  ILLINOIS 


/ 922 
K 26 


UNIVERSITY  OF  ILLINOIS 


_iiaLy,_J29_r 192S 

THIS  IS  TO  CERTIFY  THAT  THE  THESIS  PREPARED  UNDER  MY  SUPERVISION  BY 

Geo  r-ge-  -f-r-ne^  t-  -Keil  e-r 

EN  T itled  _ _ _4_  ^ Jt  he  _ ts  _ .Obtain  e d _ _Fr  pm  _ an_  _E  a 3 t er  ri 

Bituminous  Coal  Using  Diphenyl  Ether  and  Phebol  As  Solvents 

IS  APPROVED  BY  ME  AS  FULFILLING  THIS  PART  OF  THE  REQUIREMENTS  FOR  THE 
degree  OF? a_phe_lor _ _c f _ _S_c_i e_n ce_ _ _i_ n_ _C he rci cal _ _E ng i rie er in g_. 


Instructor  in  Charge 


Approved 


ACTING  HEAD  OF  DEPARTMENT  OF  -CHEMISTRY 


'^00 


Digitized  by  the  Internet  Archive 
in  2015 


https://archive.org/details/studyofproductsoOOkell 


Table  of  Contents 


I.  INTRODUCTION  PAGE 

1 . General ..1 

2.  Purpose  of  Investigation  1 

3.  Historical 1 

4.  Theoretical .6 

5.  Outline  of  Present  Investigation 8 

II.  EXPERIMENTAL 

1.  Apparatus  and  Operation . 10 

2.  Purification  of  Extracts  and  Residues 10 

3.  Large  extraction  apparatus .11 

4.  Types  of  coals  used . 12 

III.  DATA 

1.  Comparison  of  the  Solvents 13 

2.  Ultimate  Analyses  of  Coal,  Residues,  and  Extracts  . 15 

3.  General  Properties  of  Extracts  and  Residues 

(a.)  Relation  of  Extract  and  Residue  to  Coking-  . . 16 

Properties 

(b.)  Determination  of  Melting  Points  of  Extracts  . 17 
(c.)  Fractional  Carbonization  of  Residues.  ...  18 

4.  Alcoholic  Potash  Extraction 20 

IV.  SUMMARY  AND  CONCLUSIONS 21 


■ 


* • 


A STUDY  OP  THE  PRODUCTS  OBTAINED  FROM  AN  EASTERN 


HIGH  VOLATILE  COAL  USING  DIPHENYL 
ETHER  AND  PHENOL  AS  SOLVENTS 

I.  Introduction. 


1.  General. 

It  is  beginning  to  be  recognized  that  our  supply  of  coal  is  not  in- 
exhaustible, and  that  not  only  should  methods  be  adopted  for  the  conservation 
of  the  better  grades  of  coals,  but  also  means  should  be  found  for  more  effi- 
cient utilization  of  poorer  grades.  Whether  our  future  fuel  will  be  mainly 
gas,  produced  from  the  complete  gasification  of  coal,  or  gas  and  high  volatile 
coke  from  the  low  temperature  carbonization  of  coal,  or  some  other  fuel,  re- 
mains to  be  seen.  At  any  rate  poorer  grades  of  coal  will  eventually  have  to  be 
used,  and  it  seems  probable  tnat  all  coals  will  be  subjected  to  some  form  of 
carbonization,  not  only  to  save  the  valuable  by-products,  but  also  to  improve 
the  quality  of  the  product  to  be  burned.  The  number  of  coals  which  are  carbon- 
izable,  or  which  ai**  used  in  any  of  the  modem  coking  processes  is  small.  It 
is  not  definitely  known  why  all  coals  do  not  coke.  Evidently  the  constituents 
of  different  coals  are  different,  and  require  different  treatment  in  the  coking 
process.  Therefore,  it  is  necessary  to  make  complete  scientific  study  of  the 
constituents  together  with  their  behavior  during  the  carbonization  process. 

2.  Purpose  of  Investigation. 

The  purpose  of  this  investigation  has  been  to  study  the  products  ob- 
tained from  an  Eastern  High  Volatile  coal  using  phenol  and  diphenyl  ether  as 
solvents. 

3.  History. 

The  methods  of  attack  in  the  study  of  coal  are  (1)  the  use  of  solvents 


2 


and  reagents,  (2)  fractional  carbonization,  and  (3)  microscopic  examination. 

There  is  no  sharp  distinction  between  the  use  of  solvents  and  reagents;  (many 
substances  which  were  formerly  considered  to  be  solvents  hav6  been  shown  to  be 
reagents).  The  true  reagents  which  have  been  used  are  sulfuric  acid,  nitric 
acid,  caustic  alkalies,  bromine,  ozone,  and  oxygen.  Very  little  success  has 
attended  the  use  of  these  reagents  either  because  the  yields  of  products  are  so 
small,  or  the  products  themselves  are  in  such  an  advanced  stage  of  decomposition 
that  little  can  be  learned  from  them  as  to  the  constitution  of  coal,  or  because 
when  the  yields  are  high  it  is  impossible  to  separate  the  products.  Fischer 
and  Gluud^  have  recently  been  able  to  dissolve  practically  all  of  coal  by  sus- 
pending it  in  water  and  passing  a stream  of  ozone  through  it.  The  amount  that 
can  be  extracted  by  alkalies  is  increased  by  weathering  the  coal.  This  seems 
to  be  due  to  the  fact  that  ulmic  acids,  which  are  produced  by  oxidation,  are 
soluble  in  the  alkalies. 

The  use  of  solvents  in  the  study  of  coal  has  met  with  more  success  than 
the  use  of  reagents  because  the  products  are  obtained  with  the  minimum  alter- 
ation. The  problem  of  solvents  is,  however,  not  as  easy  as  the  name  would 
suggest,  because  it  is  very  hard  to  distinguish  between  solvents  and  reagents  in 
their  action  on  coal.  The  greatest  difficulty  lies  in  finding  a solvent  which 
will  extract  large  amounts  without  alteration  so  that  the  main  constituents  can 

easily  be  studied. 

2 

Bone  states  that  J.  A.  Smythe  of  Gtftt ingen  was  one  of  the  first  workers 
who  systematically  studied  tne  effects  of  such  solvents  as  benzene,  chloroform, 
ethyl  alcohol,  light  petroleum,  and  acetone  on  a brown  coal.  With  none  of 
these  solvents,  however,  could  he  extract  more  than  3%,  He  divided  his  extract 
into  portions  soluble  and  insoluble  in  ether,  obtained  the  molting  points,  and  on 
still  further  purification  by  two  different  methods,  obtained  "res ins"  which 

1 & 2.  Bone.  "Coal  and  Its  Scientific  Use."  London,  1918 


• ( , 


3 


melted  at  80°  C.,  to  which  he  assigned  the  formula  C13H26O. 

Bedson1  followed  by  Anderson2 3 4  tried  pyridine  on  a number  of  coals,  exr- 
tracting  as  high  as  20.4$  from  a Durham  gas  coal.  The  method  was  to  treat  fine- 


ly divided  coal  in  a Soxhlet  extraction  apparatus  with  pyridine.  The  excess 

pyridine  was  distilled  off  from  the  extract  under  reduced  pressure,  and  the  final 

purification  effected  by  passing  a stream  of  warm  air  over  the  extract.  The 

residue  was  also  purified  and  weighed.  From  the  results  of  experiments  on  a 

3 

number  of  coals  Bedson  concluded  that  "the  extracts  in  each  case  were  found  to 
be  rich  in  volatile  constituents,  and  in  the  coking  assay  gave  highly  intumes- 
cent  cokes,  whereas  the  residues  left  after  extraction  were  almost  devoid  of 


coking  properties".  In  general  he  found  that  there  was  no  connection  Detween 
the  amount  extracted  and  tne  volatile  content  of  tne  coal.  Air  was  not  ex- 
cluded from  tne  extraction  apparatus  in  these  experiments,  and  the  final  puri- 
fications were  made  in  a stream  of  air. 

Wheeler^and  others  also  used  pyridine  as  a solvent  followed  by  an  ex- 


traction of  tne  original  pyridine  extract  with  chloroform.  They  claim  to  have 
made  by  this  treatment  "a  complete,  or  nearly  complete  separation,  between  the 
resinous  constituents,  and  the  degradation  products  of  celluloses  of  which  coal 


is  conglomerated". 


85.33 


1.41 

10.41 


16/4 


C 

H 

N 

S 

0 


77.32 

5.14 

2.07 

1.21 

14.26 


Vol. 

31.88$ 


1 Jour.  Soc.  Chem.  Ind.  1908  Page  147 

2 Jour.  Soc.  Chem.  Ind.  1902  Page  242 

3 Jour.  Soc.  Chem.  Ind.  1908  Page  147 

4 Jour.  Chem.  Soc.  1911  Vol.  99,  page  649, 


ibid.  1913  Vol.  103,  P.  1704 


. 


4 


The  above  diagram  gives  a summary  of  their  results.  Bone  states  that 
these  results  are  open  to  three  criticisms,  namely:  (1)  "that  the  sum  total  of 
nitrogen  in  the  products  is  nearly  double  that  in  the  original  coal  treated, 
showing  that  some  of  the  solvent. nad  been  retained  by  the  various  fractions, 
despite  the  pains  to  remove  it;  (2)  that  a product  containing  as  much  as  1.71 % 
of  nitrogen  and  1.3 2%>  of  sulfur,  as  did  the  portion  soluble  in  both  pyridine 
and  chloroform,  cannot  be  regarded  as  a reasonably  pure  "resinous  body";  and 
(3)  that  inasmuch  as  the  total  oxygen  in  the  various  fractions  is  about  1.27 
times  that  in  the  original  coal,  there  had  apparently  been  some  absorption  of 
oxygen  during  the  extraction  process,  no  precaution  having  been  made  to  exclude 
air".  Hot  only  is  their  work  open  to  these  criticisms,  but  also  their  results 
show  a decrease  of  2,50%  in  the  amount  of  carbon  in  their  products  over  that 
in  the  coal.  Something  besides  a solvent  action  has  taken  place  in  the  action 
of  the  pyridine  on  the  coal. 

Wahl^  working  with  pyridine  also  found  that  there  was  no  relation  bet- 
ween the  amount  extracted,  and  the  volatile  matter.  Harger2  found  that  if  the 
extraction  was  carried  out  in  a sealed  glass  tube  under  pressure  he  could  in- 
crease the  amqnt  extracted  from  22. 5%  to  40.5^.  He  came  to  the  conclusion, 
however,  that  the  action  of  pyridine  was  not  that  of  an  ordinary  solvent,  but 
that  it  was  a depolymerising  action.  Aniline  and  quinoline  have  been  used  by 
other  investigators  with  little  success. 

Frazer  and  Hoffman3  used  phenol  in  studying  the  soluble  constituents  of 
a non-coking  coal  from  Zeigler,  Ills.  Their  method  was  to  place  the  finely 
ground  coal  in  a double  walled  copper  vessel  upon  a filtering  medium,  and  to 
treat  with  phenol  for  ten  hours  at  140°  C.  After  filtering  off  the  solution, 
the  process  was  repeated  for  three  or  four  times.  They  treated  the  extract 

with  various  reagents  and  solvents,  separating  it  into  a large  number  of  sub- 

1.  Compt.  rendus.  1912  Vol.  154,  page  1094 

2.  Jour.  Soc.  Chem.  Ind.  1914  Page  389 

3.  U.  S.  Bureau  of  Mines,  Tech.  Papfcr  Ho.  5,  1912 


* 


. 

. . . 

. 


5 

stances.  From  the  result  of  their  experiments  they  came  to  the  following  con- 
clusions: 

"In  the  lack  of  evidence  to  the  contrary  it  is  assumed  that  the  coal 
substance  soluble  in  phenol  is  present  in  the  coal  as  such. 

"The  authors  believe,  as  a result  of  the  investigation,  that  some  of  the 
substances  isolated  very  closely  approach  compounds." 

Parr  and  Hadley‘S  using  phenol  as  a solvent  found  that  the  amount  which 
could  be  extracted  was  definite,  and  susceptible  of  quantitative  determination. 
The  extract  had  a rather  definite  melting  point,  and  a decomposition  point 
above  the  melting  point.  This  extract  was  found  to  be  the  vital  constituent 
concerned  in  the  coking  of  the  coal.  They  were  able  to  modify  tne  coking  qual- 
ities of  the  coal  by  oxidizing  either  the  residue,  or  extract,  or  both. 

Cherry2  working  with  the  same  solvent  also  found  that  oxidation  of  the  residue 
destroyed  that  coking  property  of  the  coal  altnough  tne  coking  principle  was  in 
the  extract.  He  explained  this  by  considering  that A the  fusion  temperature  a 
reaction  took  place  between  the  oxidized  cellulosic  constituents  and  the  res- 
inic  bodies,  altering  the  latter  in  such  a manner  that  they  were  not  able  to  bind 
the  coal  particles  together. 

Fischer  and  Gluud3  of  the  Kaiser  Wilhelm  Institute  for  Coal  Investi- 
gation have  recently  worked  with  benzene  at  temperatures  ana  pressures  approx- 
imating the  critical  constants  of  the  solvent.  They  carried  out  tne  extraction 
in  a steel  bomb  with  the  coal  suspended  in  a wire  gauge  basket.  The  temperature 
employed  was  275°  C.  A coal  which  by  extraction  in  a Soxhlet  extraction  app- 
aratus gave  only  1$  extract,  yielded  6.7$  in  the  bomb.  On  pouring  the  extract 
dissolved  in  some  benzene  into  petroleum  ether,  a brown  powder  separated  out 

which  soicened  at  1400  and  melted  at  150®  c.  They  observed  that  no  gas  was 
liberated  when  the  bomb  was  opened  and  took  this  as  an  indication  that  no  decom- 

1.  Bulletin  76.  Univ.  of  111.  Exp.  Station 

2.  Thesis  B.  S.  Univ.  of  111. 

5.  3 one.  "Coal  and  Its  Scientific  Use"  London  191ft 


. 


■ 


6 


position  had.  taken  place.  The  question  as  to  whether  a temperature  this  nigh 
does  not  in  some  way  alter  the  coal  substaiice  itself,  has  not  been  settled.  It 
would  seem  from  these  investigations  that  one  of  the  best  fields  for  solvent 
work  lies  in  extraction  under  pressure,  and  at  comparatively  high  temperatures. 

4.  Theory. 

The  terms  'cellulosic  constituent'''  and  "resinic  bodies"  have  already 
been  mentioned  in  connection  with  Cherry’s  investigation.  These  terms  have 
cone  into  the  literature,  and  have  been  used  more  or  less  indefinitely  to  denote 
the  residues,  and  extracts  from  the  treatment  of  coals  with  various  solvents. 
Lewes^  was  one  of  the  first  to  use  these  terms.  He  states  that  coal  is  made  up 
of  the  carbon  residuum  from  the  decomposition  of  the  humus  bodies  (cellulosie 
derivatives)  together  with  humus  bodies  in  varying  states  of  decomposition, 
resin  bodies,  and  hydrocarbons.  His  resin  bodies  are  formed  by  the  oxidation 
of  such  extractive  matters  as  gums,  mucilage,  vegetable  jelly,  plant  resins, 
etc.  Since  the  resin  bodies  are  more  resistant  to  decay  they  accumulate  in  the 
masses  of  decaying  vegetable  matter.  The  hydrocarbons  are  formed  from  the  resin 
bodies  by  isomeric  or  other  changes  brought  about  by  heat  and  pressure.  He 
states  that  the  "factor  which  has  made  the  oldest  coal  a coking  ooal  is  the  more 
complete  degredation  of  the  humus  with  the  elimination  of  oxygen  bringing  the 
resin  bodies  and  hydrocarbons  up  to  a percentage  which  will  supply  enough  luting 
material  on  decomposition  to  give  a satisfactory  coke."  Although  some  of  his 
assumptions  as  to  tne  formation  and  composition  of  coal  may  be  correct,  they 
need  to  be  revised  as  the  result  of  later  investigations,  especially  those  of 
Thiessen.~  It  has  been  shown  rather  conclusively  that  free  carbon  does  not 
exist  in  coal.  The  newer  and  more  correct  view  is  that  the  extractive  matters 

are  the  decomposition  products  of  cellulose,  and  are  in  no  way  to  be  considered 
as  resins. 

1.  Lewes.  "The  Carbonization  of  Coal."  1914 

2.  Bulletin  117,  U.  S.  Geological  Survey. 


* 

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. 


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«■ 


. 


' 


• * f 


7 


Burgess  and  Vftieelerl  fractionally  distilled  several  English  coals  in  a 
small  platinum  retort.  They  summarised  their  results  as  follows:  (1)  "there 

is  a well  defined  decomposition  point  between  700°C.  and  800°  C.,  which  corres- 
ponds to  a marked  increase  in  the  quantity  of  hydrogen  evolved;  (2)  with  bit- 
uminous coals  the  quantity  of  hydrogen  evolved  falls  off  at  temperatures  above 
y00°  C.,  but  with  anthracitic  coals  it  is  maintained  up  to  1100°  C;  (3)  the 
evolution  of  hydrocarbons  of  the  paraffin  series  ceases  almost  entirely  at  temp- 
eratures above  700°  C.;  (4)  ethane,  propane,  butane,  and  probably  higher  members 

of  the  paraffin  series  foiro  a large  percentage  of  the  gases  evolved  below  450°  C.; 
(5)  the  rate  at  which  the  carbon  monoxide  is  evolved  is  uniform  throughout  a dis- 
tillation at  any  one  temperature,  ana  is  maintained  rignt  up  to  the  end,  while 
the  rates  in  the  case  of  other  gases  fall  off."  From  these  statements  they  con- 
cluded that  coal  consists  of  two  parts  of  different  degrees  of  stability,  the 
less  stable  or  resinic  portion  decomposing  first  to  give  chiefly  paraffin  hydro- 
carbons, while  the  more  stable  cellulosic  portion  decomposes  yielding  hydrogen. 
Very  probably  the  difference  between  one  coal  and  another  is  determined  mainly 
by  the  proportion  in  which  these  two  types  of  compounds  exist,  anthracite,  for 
example  containing  but  little  of  the  more  unstable  constituents.  To  further 
verify  their  conclusions  they  separated  coal  into  the  three  portions  mentioned 
on  page  3,  and  fractionally  distilled  these  products. 

Porter  ana  Taylor^  carried  on  a series  of  similar  experiments  with  Am- 
erican coals.  In  general  they  do  not  agree  with  Burgess  and  Wheeler.  They 
concluded  from  their  experiments  that  the  first  decomposition  occurring  in  any 
type  of  coal  is  the  breaking  down  of  certain  oxygen  bearing  substances  related  to 
cellulose,  the  products  being  chiefly  water,  carbon  dioxide,  and  carbon  monoxide. 
The  "resinic1'  portion  decomposes  v/ith  the  formation  of  paraffin  hydrocarbons  with 
probably  hydrogen  as  a direct  decomposition  product.  Their  conclusion  as  to  the 
early  decomposition  of  the  cellulosic  portion  is  more  logical  than  that  of  Bur- 

1.  Jour.  Chem.  Soc.  97,  1910,  pp.  1917  - 1935;  99,  1911  pp.  650  -657 

— , .,,f oxter-  Bartm-.,  MO.  IT.  Snyeua  of  Ttliar.a* 


V 

' 


. . - 

■ 


8 


gess  ana  Wheeler. 

In  Doth  Burgess  and  Y/heeler's,  and  Porter  and  Taylor's  work  no  reference 
has  been  made  to  the  presence  of  nitrogenous  constituents.  Bone  believes  that 
the  presence  of  these  constituents  has  some  bearing  on  the  coking  properties  of 
the  coals.  Recently  there  has  appeared  an  article-1-  in  which  a third  class  of 
bitumen  present  in  coal  is  mentioned.  It  is  supposed  to  be  the  degraded  product 
of  the  nitrogen  proteins,  and  is  intermediary  in  character.  There  is  at  present, 
however,  no  experimental  evidence  for  the  existence  of  this  third  group,  and  its 
influence  on  the  coking  properties,  if  present,  is  negligible.  No  selective 
solvent  has  been  found  for  this  proteid  constituent. 

The  term  "resinic"  is  more  or  less  unfortunate  in  that  many  have  taken 
it  to  mean  that  this  material  is  derived  from  the  resins  of  the  plant  substances 
from  which  coal  is  formed.  The  "resin  bodies"  should  be  distinguished  from  the 
original  gum  or  fossil  resins.  Although  the  extractive  material  may  contain 
some  gum  and  fossil  resins,  by  far  the  larger  part  of  this  material  is  the  dec- 
omposition product  of  the  cellulosic  material  of  the  plant  substances.  In  this 
investigation  the  soluble  and  insoluble  portions  of  the  coal  will  be  designated  by 
extract  and  residue  respectively.  The  view  has  been  developed  at  the  University 
of  Illinois  that  for  a coal  to  coke  it  must  contain  sufficient  of  the  "resinic 
constituent"  which  does  not  distill  without  decomposition,  to  furnish  a binder 
for  the"cellulosic  portion".  There  must  be  no  reaction  with  oxygen  at  the  crit- 
ical temperature > or  large  deliverance  of  gases  to  prevent  the  luting  material  from 
cement ing  the  particles  together. 

5.  Outline  of  Investigation. 

It  has  been  the  object  of  this  investigation  to  make  a comparison  of  the 
two  solvents,  diphenyl  ether  and  phenol.  Phenol  has  been  used  frequently  as  a 
solvent  for  coal.  Up  to  the  present  time,  however,  no  mention  has  been  made  of 
the  use  of  diphenyl  ether  in  coal  investigation.  Preliminary  investigation  of 

1.  &as  Journal  (London)  157  No.  5060,  p.  28 


' 


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9 

this  compound,  seemed  to  show  that  it  would  extract  a comparatively  large  amount 
from  coals,  and  it  was  thought  that  perhaps  it  might  he  used  in  place  of  phenol, 
pyridine,  and  other  solvents  used  heretofore. 

The  study  of  the  action  of  these  solvents  has  involved  the  following 

points: 

(1)  A comparison  of  the  amounts  extracted  from  an  Eastern  Bituminous 
coal,  and  a weathered  lignite. 

(2)  Development  of  an  apparatus  and  method  for  extracting  comparatively 
large  amounts  of  coal. 

(3)  Determination  of  the  amount  of  decomposition  during  the  extraction. 

(4)  Determination  and  comparison  of  the  ultimate  analyses  of  the  diff- 
erent residues  and  extracts  with  the  original  coal. 

(5)  Determination  of  the  influence  of  the  various  products  in  coking 

tests. 

(6)  Determination  of  the  melting  points  of  the  two  extracts. 

(7)  Fractional  carbonization  of  residues  with  a comparison  of  the  res- 
ults. 

(8)  Determination  of  the  amount  extracted  by  a 10^  alcoholic  potash 

solution. 


II.  Experimental 


10 


1.  Apparatus  and  procedure. 

A number  of  different  metiiods  were  tried  in  extracting  the  coal.  The 
method  in  which  the  Soxhlet  Extraction  apparatus  was  used  was  discarded  when  it 
was  found  that  this  apparatus  would  not  stand  the  difference  in  temperature  and 
consequent  expansion,  without  breaking.  The  method  finally  employed  ror  small 
quantities  was  essentially  that  used  by  Cherry-*-.  Five  grams  of  coal  were  placed 
in  an  Erlenmeyer  flask,  dried  at  105°  C.  for  one  hour  with,  a stream  of  dry  nitro- 
gen passing  over,  50  - 60  c.  c.  of  the  solvent  added,  and  the  mixture  refluxed 
gently  for  24  hours  at  the  boiling  points  of  the  solvents.  The  flasks  were  heat- 
ed in  a nichrome  wound  electric  resistance  furnace,  insulated  from  radiation  by 
asbestos  packing. 

After  the  mixture  had  refluxed  for  24  hours,  the  hot  solution  was  allow- 
ed to  cool  slightly,  and  was  then  filtered  through  a Buchner  funnel.  The  phenol 
residue  was  washed  twice  with  alcohol,  and  then  with  etner.  After  washing  it 
was  quickly  replaced  in  the  flask  and  refluxed  again  for  24  hours  with  fresh 
phenol.  The  diphenyl  ether  residue  v/as  washed  with  ether  alone.  Two  extractions 
were  made  after  it  was  found  that  only  a very  small  quantity  was  extracted  on  the 
third  and  fourth  treatments. 

2.  Purification  of  extracts  and  residues. 

The  solutions  from  the  two  extractions  were  united,  and  most  of  the  ex- 
cess phenol  distilled  off.  Both  distillation  under  reduced  pressure  and  under 
atmospheric  pressure  were  used.  When  reduced  pressure  v/as  used,  nitrogen  v/as 
allowed  to  bubble  through  the  solution  instead  of  air  in  order  to  prevent  oxida- 
tion. Reduced  pressure  distillation  was  finally  abandoned,  because  the  final 
temperature  employed  in  the  purification  was  slightly  above  the  boiling  point  of 
the  phenol.  Before  all  of  the  phenol  v/as  distilled  off,  the  contents  of  the  dis- 
tilling flask  were  allowed  to  cool  slightly  and  were  transferred  to  a tared  Er- 

1.  Thesis,  B.  S.  Univ.  of  111. 


■ 


■ 


' 


‘ 


I 


11 


lenmeyer  flask,  and  the  final  purification  made  by  passing  a stream  of  dry  nitro- 
gen slowly  over  the  extract  at  190°  - 200°  C.  until  no  odor  of  phenol  could  be 
detected  in  the  nitrogen  passing  off*  The  nitrogen  used  was  obtained  in  cylin- 
ders from  the  Linde  Air  Products  Co.  This  was  further  purified  by  passing  it 
through  solutions  of  alkaline  pyragallol,  and  concentrated  sulfuric  acid  in  order 
to  remove  any  oxygen  and  moisture  that  might  be  present. 

The  diphenyl  ether  extract  was  purified  in  the  same  manner  except  that 
the  final  temperature  employed  was  260°  - 270°  C. 

The  residues  were  purified  by  washing  first  with  alcohol,  and  then  with 
ether  in  a Soxhlet  extraction  apparatus,  or  on  a Buchner  funnel.  The  last  traces 
of  the  solvents  were  removed  oy  passing  dry  nitrogen  over  the  residues  at  temp- 
eratures slightly  above  the  uoiling  points  of  the  solvents. 

3.  Large  Extraction  Apparatus. 

It  was  found  that  in  both  the  diphenyl  ether  and  phenol  extractions,  the 
coal  tended  to  cake  on  the  bottom,  causing  bumping,  and  perhaps  overheating  of  the 
coal.  In  order  to  prevent  this,  and  to  facilitate  the  handling  of  larger  quanti- 
ties or  the  coal,  a larger  extraction  apparatus  was  devised.  It  consisted  of  a 
cylindrical  iron  vessel  6 inches  in  diameter,  and  7 inches  deep  with  an  iron  cover 
ground  to  fit,  and  fastened  with  six  3/8  inch  machine  uolts.  A lead  gasket  was 
used  to  naxe  a tight  seal.  A one  inch  pipe  coupling  was  uriven  into  the  hole 
already  in  the  center  of  the  cover,  and  a pipe  two  feet  long  screwed  into  tne 
coupling.  A 3/8  incn  brass  rod  carrying  two  stirring  padulos  passed  down 
through  tnis  pipe.  Loose  fitting  brass  bushings  were  driven  into  each  end  of 
the  pipe.  It  acted,  not  only  as  a means  of  supporting  the  stirring  mechanism, 
but  also  as  an  air  condensor  for  the  condensation  of  the  solvents.  The  stirring 

mechanism  was  driven  by  a 1/16  H.  P.  motor,  the  speed  of  which  was  reduced  by  a 
system  of  pulleys  to  50  - oO  R.  P.  M. 


- 


« 

r 

<b 

8 


12 

The  method  of  procedure  using  tnis  apparatus  was  similar  to  that  describ- 
ed above.  200  grams  of  coal  were  placed  in  the  vessel  and  the  lid  oolted  on. 

The  condenser  pipe  was  removed  and  replaced  by  a stopper  carrying  a thermometer 
and  two  pieces  of  glass  -cubing.  The  apparatus  was  placed  in  an  electric  resis- 
tance furnace  and  heated  to  10b°  0.  for  one  hour  with  a stream  of  dry  nitrogen 
passing  through.  In  this  manner  the  coal  could  be  dried  without  oxidation. 

After  the  coal  was  dry  the  stopper  was  removed  and  1000  - 1200  c.  c.  of  the  sol- 
vent added.  The  condenser  tube  and  stirring  mechanism  were  then  replaced  and 
the  extraction  was  carried  out  for  eight  hours,  the  tenroerature  of  the  furnace 
being  kept  slightly  above  the  boiling  point  of  the  solvent.  The  residues  and 
extract  were  treated  in  the  some  manner  as  given  above 

Table  I. 

Diphenyl  Ether  Extractions. 


Hun 

In  flask  with 
small  quantities. 

In  large  extract' 
ion  apparatus. 

1. 

Jellico  Coal 

6.68 

6.0 

2. 

Jellico  Coal 

6.66 

4.0 

3. 

Jellico  Coal 

5.14 

5.5 

These  experiments  proved  that  the  large  apparatus  was  capable  of  extract- 
ing practically  the  same  amount  as  was  extracted  by  the  other  method,  and  it  was 
much  faster. 

A Jellico  coal  of  the  Eastern  High  Volatile  type  from  Harlan  County, 
Kentucky  was  used  in  most  of  these  experiments.  In  a few  tests  a weathered 
lignite  from  Estevan,  Manitoba  was  used.  The  proximate  analyses  are  given 
below. 


. 


13 


Table  II. 


Proximate 

Analyses. 

Jellico 

Lignite 

Moisture 

1.75 

13.87 

Ash 

2.64 

6.63 

Volatile 

36.33 

36.02 

Fixed  Carbon 

59.28 

43.50 

Sulfur 

0.65 

Ill*  Data  and  Discussion. 

1.  Comparison  of  the  Solvents. 

In  order  to  find  out  which  solvent  extracted  the  largest  amount  from  the 
coals,  a number  of  tests  were  made.  The  results  are  given  in  the  table  below. 

Table  III. 

.Amounts  Extracted. 


No. 


Coal 


% extracted 
by  Phenol 


% extracted  by 
Diphenyl  Ether 


Air  dry. 

A.  & M.  free 

Air  dry 

A.  & M. 

1 

Jellico 

20,82 

21.81 

6.68 

6.98 

2 

Jellico 

21.05 

22.03 

6.66 

6.97 

3 

Jellico 

5.14 

5.37 

4 

Weathered  Lignite 

7.85 

9.89 

1.14 

1.45 

5 

Weathered  Lignite 

0.90 

1.15 

These  tests  show  that  phenol  extracted  three  times  as  much  from  the  Jel- 
lico  coal,  and  seven  times  as  much  from  the  Lignite  as  the  diphenyl  ether.  The 
extract  in  each  case  was  in  a blaclc  shiny  mass,  but  on  powdering  it  had  a distinct 
ly  brown  color.  The  residues  resembled  the  original  coal.  However,  the  sum  of 
the  extract  and  residues  in  neither  case  added  up  to  exactly  the  amount  of  coal 
taken.  It  was  much  easier  to  work  with  the  diphenyl  ether. 


* 


' 


. 


14 


Table  IV. 

Weight  of  Extract  and  Residue  from  Jellico  Coal  with  Phenol  as  the  Solvent. 


of  coal 

Wt.  of  extract 

Wt.  residue 

Total 

Difference 

10.000 

8.190 

2.082 

10.272 

+ 0.272 

10.000 

8.216 

2.105 

10.321 

+ 0.321 

Table  V. 

Weight  of  Extract  and  Residue  from  Jellico  Coal 
using  Diphenyl  Ether  as  the  Solvent. 


of  coal  1 

,7t . of  extract 

Wt.  of  residue 

Total 

Difference 

5.000 

0.318 

4.705 

5.013 

+0.013 

5.000 

0.334 

4.716 

5.050 

+0.050 

Table  IV  shows  that  the  phenol  has  either  decomposed  or  has  reacted  in 
some  manner  with  the  coal  substance,  and  is  held  either  in  the  extract  or  residue 
or  in  both  in  such  a manner  that  it  can  not  be  removed  by  ordinary  methods. 

Parr  and  Hadleyl  attributed  this  error  to  the  decomposition  of  phenol.  "Further- 
more oxidation  or  absorption  of  water  by  either  extract  or  residue  would  cause 
an  increase  in  weight,  and  would  tend  to  augment  the  plus  error." 

In  the  case  of  the  diphenyl  extractions  the  sum  of  the  two  products  is 
within  the  limit  of  experimental  error.  But  here  the  question  of  the  decompos- 
ition of  the  extract  and  residue  under  the  purification  treatment  must  be  tahen 
into  account.  At  the  temperature  of  the  boiling  point  of  dipnenyl  ether  (250°C.) 
there  is  undoubtedly  some  decomposition  of  the  coal  substance.  In  driving  off 
the  last  traces  of  diphenyl  ether  with  nitrogen  at  a temperature  of  260  - 270°  C. 
the  diphenyl  ether  was  a light  straw  color,  and  smelled,  as  if  some  of  the  coal 
substance  had  decomposed.  If  decomposition  does  take  place  the  sum  of  the  pro- 
ducts would  be  increased  by  the  amount  of  the  decomposition,  and  the  plus  error 
would  be  increased. 

1.  Bulletin  76.  Univ.  of  111.  Eng.  Expt.  Station. 


. 


15 


Table  VI. 

2.  Ultimate  Analysis  Diphenyl  Ether  Extraction. 


fixfcjrasj?.. 

c7 


Dry  % Dry 

Dry 

Coal 

Yield 

6.05 

93.95 

Moisture 

Ash 

0.74 

0.04 

3.19 

Carbon 

85.10 

5.15 

81.75 

Hydrogen 

5.52 

0.33 

4.66 

Oxygen 

6.32 

0.38 

CO 

. 

Nitrogen 

1.83 

0.11 

1.60 

Sulfur 

0.49 

0.03 

0.62 

B.  T.  U. 

15,150 

916 

14,250 

Jellico  Coal 


% Dry 
Coal 

Total 

As  Reed. 

Dry 

1.75 

2.99 

3.03 

2.64 

2.71 

76.75 

81.90 

80.75 

82.25 

4.56 

4.89 

5.63 

5.79 

7.50 

7.88 

8.63 

8.78 

1.50 

1.61 

1.65 

1.68 

0.58 

0.61 

0*65 

0.67 

13,300 

14,216 

14,348 

14,610 

Table  VII. 

Ultimate  Analysis  Phenol  Extraction. 

Extract  Residue  Jellico  Coal 


Dry 

7°  Dry 

Dry  fa  Dry 

Total 

As  Reed. 

Dry 

Coal 

Coal 

Yield 

15.28 

84.72 

Moisture 

0.81 

1.75 

Ash 

c 0 . 81 

0.12 

3.59 

3.04 

3.16 

2.64 

2.71 

Carbon 

84.50 

12.80 

80.95 

68.50 

81.30 

80.75 

82.55 

Hydrogen 

4.81 

0.74 

4.85 

4.10 

4.84 

5.68 

5.79 

Oxygen 

7.60 

1.16 

8.20 

6.95 

8.11 

8.63 

8.78 

Nitrogen 

1.78 

0.27 

1.64 

1.39 

1.66 

1.65 

1.68 

Sulfur 

0.50 

0.08 

0.68 

0.57 

0.65 

0.65 

0.67 

B.  T.  U. 

14,710 

2,235 

14,148 

12,000 

14,235 

14,348 

14,600 

■ • 


* 


. 

• 

. 

- 


. 


16 

Carbon  was  determined,  in  the  Parr  Total  Carson  apparatus,  the  Calorific 
value  in  the  Parr  Oxygen  Bomb  Calorimeter,  and  nitrogen  by  the  Kjeldahl  method. 
Dulong’s  formula  was  used  to  calculate  the  hydrogen  and  oxygen  values. 

An  examination  of  the  ultimate  analyses  shows  a decrease  in  both  hydrogen 

a.n<L  OJUn  en- 

Aand  a slight  increase  in  Carbon.  This  would  seem  to  indicate  that  some  of  the 
solvents  were  retained  in  the  products.  There  is  also  a loss  in  calorific  val- 
ue. The  determination  of  the  calorific  value  of  the  extracts  was  exceedingly 
difficult  owing  to  their  high  volatility.  An  increase  in  ash  is  also  shown. 

Part  of  this  might  be  accounted  for  by  the  solution  of  some  of  the  iron  of  the 
extraction  apparatus,  although  preliminary  tests  showed  that  the  solvents  had  very 
little  effect  on  either  iron  or  brass. 

3.  General  Properties  of  Extracts  and  Hesiaues. 

(a)  Relation  of  Extract  and  Residue  to  Coking  Properties. 

The  Jellico  coal  used  in  this  investigation  produced  an  excellent  coke 
by  the  ordinary  volatile  matter  method.  In  order  to  prove  conclusively  which 
part  was  responsible  for  the  coking  or  non-coking  of  coals  a number  of  tests  were 
made  witn  different  substances.  The  unoxidized  residue  from  the  diphenyl  ether 
extractions  gave  almost  as  good  a coke  as  the  original  coal,  althougn  it  was  not 
so  firm.  The  unoxidized  residue  from  the  phenol  extractions  was  only  very  poor- 
ly held  together,  and  would  oe  termed  non-coking.  On  recombining  the  extracts  anc 
residues  in  the  proportions  in  the  original  coal,  the  coke  could  scarcely  be  dis- 
tinguished from  that  of  tne  original  coal.  The  extracts  themselves  swelled  on 
heating  and  formed  a very  light  large  celled  fluffy  coke.  It  was  comparatively 
easy  to  destroy  the  coking  properties  by  oxidxzing  the  residues,  but  more  diffi- 
cult by  oxidizing  only  the  extract.  From  these  tests  it  was  decided,  as  Parr  and 
Hadley-^-,  Cherry^,  and  others  have  shown,  that  the  coking  principle  is  in  tne  ex- 
tract, and  tnat  tne  extract  decomposes  above  its  melting  point  to  furnish  the 

1.  Bulletin  76,  Univ.  of  111.  Eng.  Expt.  Station 

2.  Thesis,  B.  S.  Univ.  of  111. 


. 


a ’■ 

. 


■ 


17 


binder  for  the  residue.  In  the  light  of  these  facts,  it  ought  to  be  possible  to 
coke  almost  any  substance  by  adding  sufficient  amount  of  the  correct  kind  of  bind- 
ing material  to  it.  The  following  tests  were  made  in  order  to  test  the  effect 
of  adding  the  diphenyl  ether  extract  to  various  substances. 

Table  VIII. 


Test  No. 

Material  to  be  Bonded 

% Extract  in 
Total  mass 

Result 

1 

n 

Magnesium  Carbonate 

10 

Powder 

2 

Magnesium  Carbonate 

20 

Powder 

3 

Magnesium  Carbonate 

33 

Silvery  coke  structure 

4 

Lignite  Coal 

10 

Powder 

5 

Lignite  Coal 

20 

Powder 

6 

Lignite  Coal 

33 

Very  weak  coke  structure, 
dull 

7 

Phenol  Res.  Lignite 

10 

Powder 

8 

Phenol  Res.  Lignite 

20 

Powder 

9 

Phenol  Res.  Lignite 

33 

Very  weak  coke  structure, 
dull 

These  tests  indicate  that  is  possible  to  form  a semblance  of  a coke 
structure  provided  there  is  suffinient  bond  forming  material  present.  These  cokes 
were  in  no  way  comparable  to  those  formed  from  good  coking  coals.  It  must  be 
remembered,  also,  that  these  tests  were  carried  out  under  the  most  favorable  con- 
ditions and  probably  under  conditions  less  favoraole  the  same  results  might  not 
be  obtained.  The  percentage  of  extracts  needed  for  forming  a coke  structure 
would  probably  not  be  the  same  for  extracts  from  different  coals,  and  from  the 
same  coals  using  different  solvents. 

The  Magnesium  carbonate  was  used  to  determine  the  effect  of  the  deliver- 
ance of  COg  at  a temperature  near  which  coke  formation  is  supposed  to  take  place. 

(b)  A comparison  of  the  melting  points  of  the  two  extracts  gave  the 
following  results: 


- 


■ 


> 


18 


Table  IX. 

Substance  Melting  Point  Degrees  C. 

Diphenyl  Extract  210  - 245  Not  sharp 

Phenol  Extract  185  - 190  Rather  sharp 

The  melting  points  were  taken  by  gradually  raising  the  temperature  of  an 
iir  bath,  in  which  a cube  of  the  extract  was  suspended  from  a wire,  until  the  ex- 
tract melted  and  dropped  off.  Some  softening  took  place  before  the  temperatures 
listed  above.  The  diphenyl  ether  residue  did  not  have  a distinct  melting  point, 
and  did  not  become  very  fluid  at  any  tine.  It  contains  constituents  which  have 
a higher  and  wider  range  of  melting  points  than  the  phenol  extract.  W.  S.  Haw- 
thorne working  at  the  University  of  Illinois,  sound  the  softening  of  this  coal 
took  place  between  3too  c.  and  3 70°  C. 

(c)  Fractional  Carbonization  of  Residues. 

In  order  to  determine  the  effects  of  removing  different  amounts  of  the 
extractive  matters,  fractional  carbonization  tests  were  made  on  the  diphenyl  ether 
ana  pnenol  residues.  The  carbonizations  were  carried  out  in  a glass  retort  heat- 
ed by  an  electric  resistance  furnace.  The  tar  and  water  were  condensed  out  in  a 
small  distilling  flask  the  Mg  removed  by  10$>  sulfuric  acid,  and  the  gases  dried 
by  passing  through  a CaClg  tube.  The  temperature  was  raised  gradually,  the  total 
carbonization  time  varying  from  4-5  hours.  .Amounts  of  tar  and  water  varied 
from  2-5  grams.  The  retort  was  swept  out  with  nitrogen  before  and  after  each 
run.  The  amount  of  nitrogen  in  the  retort  at  the  beginning  of  each  run  was  not 
measured  so  that  the  amount  of  nitrogen  delivered  by  the  coal  could  not  be  deter- 
mined. 


■ 


Fractional  Carbonization  or  Jellico  Coax 
Table  X. 

Residues 

19 

Gas  Analysis 

(112  free  basis) 

Percentage  Composition 

Diphenyl  Residues 

Phenol  Residues 

Temp,  inside  retort 

360° 

410° 

460° 

360° 

410° 

4o0° 

Carbon  dioxide 

69.6 

44.6 

40.1 

74.6 

47.4 

16.3 

Oxygen 

7.o 

£.2 

2.9 

0.7 

3.2 

1.2 

Ethylene  Series 

6.3 

o«2 

6.7 

1.7 

0.1 

7.3 

Benzene  Series 

0*0 

O.o 

0.4 

0.0 

0.5 

0.9 

Hydrogen 

D#  o 

6.5 

10.3 

10  .a 

10.0 

22.6 

Carbon  Monoxide 

b.o 

6.5 

3.5 

1.7 

7.4 

6.7 

Metnane 

5.1 

13.2 

24.7 

2.o 

12.7 

26.1 

Ethane 

19.0 

10.4 

12.7 

18.9 

TOTALS 

100.0 

100.0 

100.0 

100.0 

100.0 

100.0 

Table  XI. 

C.  C. 

of  Gaseous  Products 

per  50  grams. 

Diphenyl  Residues 

Phenol  Residues 

Temp,  inside  retort 

360° 

410° 

4600 

360° 

410° 

* 

4600 

Carbon  dioxide 

106.0 

167.0 

418.0 

76.5 

216.5 

188.0 

Oxygen 

11.5 

12.1 

30.0 

8.9 

14.5 

13.4 

Ethylene  Series 

9.6 

23.1 

70.0 

1.8 

27.8 

84.2 

Benzene  Series 

0.0 

2.2 

4.0 

0.0 

2.4 

9.8 

Hydrogen 

8.6 

24.2 

108.0 

10.7 

45.9 

260.5 

Carbon  Monoxide 

8.6 

24.2 

38.0 

1.8 

33.9 

76.8 

Methane 

TV 

Ethane 

7.7 

49.6 
1.59 
on.  4 

256.2 

1.3 

109.8 

2.7 

57.5 

1.5 

57.5 

501.8 

1.42 

218.5 

TOTALS 

152.0 

373.8 

1034.0 

102.4 

456.0 

1153.0 

* Residue 

not  from  same  extraction  as 

4 and  5. 

• 

. 

. 

. 

• 

' 

1 


20 


Carton  dioxide  forms  a large  percentage  of  the  gases  delivered  np  to 
460o  C.  The  phenol  residue,  which  contains  more  of  the  "cellulosic  constituent", 
shows  a marked  increase  in  the  amount  of  hydrogen  delivered  over  that  delivered 
by  the  diphenyl  ether  residues.  Almost  no  "benzene  series,  and  only  a small  per- 
centage of  the  ethylene  series  and  carton  monoxide  are  given  off  up  to  460°  C, 
Xethane  and  ethane  begin  to  be  delivered  in  comparatively  large  amounts  at  about 
410°  C. 

4.  Alcoholic  potash  extraction. 

In  order  to  determine  what  effect  alcoholic  potash  would  have  on  the 
coal,  20  grams  were  refluxed  with  a 10 % solution  of  XOH  in  95 % ethyl  alcohol. 

The  solution  was  filtered,  the  filtrate  acidified,  and  the  brown  precipitate  fil- 
tered off.  The  amount  extracted  by  one  treatment  was  Z.oZ%  on  the  ash,  moisture 
free  basis.  As  much  as  6.49 % could  be  extracted  by  three  successive  treatments, 
although  the  last  two  extractions  took  out  chiefly  ash.  The  amount  of  ash  free 
substance  extracted  was  practically  5%  of  the  coal.  The  residues  alone  from 
these  treatments  weighed  more  than  the  original  coal,  indicating  that  it  was  im- 
possible to  remove  all  of  the  XOH  which  had  reacted  in  some  manner  with  the  coal. 
The  residue  had  no  caking  properties,  while  the  extract  swelled  in  much  the  same 
manner  as  the  phenol  or  diphenyl  extracts.  Ho  coke  was  formed  on  heating  the  re- 
combined constituents.  Saponification  by  means  of  alcoholic  potash  should  re- 
move all  the  true  resins  present  in  the  coal  along  with  the  ulmic  acids.  The 
excess  of  the  amount  extracted  by  phenol  over  this  amount  might  be  taken  as  an 
indication  of  the  amount  of  cellulosic  degradation  products  present  in  the  coal. 
This  would  not  be  reliable,  however,  since  it  has  not  been  shown  that  the  phenol 
removes  ulmic  acids. 


■ 


■ 


21 

IV.  Summary  and  Conclusions. 

1.  Diphenyl  ether  is  not  a satisfactory  solvent  for  the  types  of  coal 
used  in  this  investigation,  the  residues  having  practically  as  good  coking  qual- 
ities as  the  original  coal.  It  is  much  easier  to  handle  than  phenol. 

2.  Che  diphenyl  ether  extracts  contain  constituents  which  have  a higher 
and  wider  range  of  melting  points,  a higher  carbon  and  hydrogen  content,  and  a 
lower  oxygen  content  than  the  corresponding  phenol  extracts.  This  seems  to  in- 
dicate that  diphenyl  ether  extracts  more  hydrocarbons  than  phenol. 

3.  The  temperature  used  in  the  treatment  with  diphenyl  ether  undoubt- 
edly causes  some  decomposition  of  the  coal. 

4.  The  coking  principle  is  in  the  extract.  The  coking  property  can 
be  altered  by  oxidation  of  either  the  extract  or  residue,  the  oxidation  of  the 
residue  taking  place  morequickly  and  completely. 

5.  Part  of  the  phenol,  and  perhaps  some  of  the  diphenyl  ether,  is  re- 
tained by  tne  extract  or  residue  or  by  both  even  after  the  most  careful  treatment 
for  its  removal,  indicating  that  it  has  decomposed  or  has  reacted  in  some  manner 
with  the  coal  substance. 

6.  It  is  possible  to  form  a semblance  of  a coke  structure  provided 
enough  extract  is  added  to  a lignite  coal  or  residue.  The  amount  needed  is  great- 
er than  that  contained  in  a good  coking-  coal. 

7.  Carbon  dioxide  forms  a large  proportion  of  the  gases  given  off  by 
the  residues  up  to  460°  C.  The  paraffin  series  begins  to  be  liberated  in  quan- 
tity at  about  400°  C.  A larger  amount  of  hydrogen  is  given  off  by  the  phenol 


residues  than  by  the  dipnenyl  ether  residues  up  to  460°  C 


, ; - a 

‘ 


